You don’t expect to hear such grown-up sentiments from Bill Nye, the bowtie-branded, nationally known nerd and former host of a beloved children’s show.

But there he was, popping peanuts, sipping a beer and taking in the waving, excited women on the big screen at Safeco Field. Well, then.

Nye, 57, had just thrown out the first pitch at the Mariners-Angels game, in honor of the 20th anniversary of “Bill Nye the Science Guy,” which was started by a team in Seattle, picked up by Disney and aired on public television from 1993 to 1998.

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What you also didn’t expect was that even after two decades, Nye’s staying power is as strong as ever. The New York Times was right when it called him “The Springsteen of the Nerds.”

Everywhere Nye went in his weathered Filson hat and trench coat one recent night, people turned into the kids they once were. Time and again came the double-take, the moment of recognition, the smile and then: “Bill Nye the Science Guy!”

It came from people on the street, young men hanging out of the windows of cars.

When he passed a black-clad clutch of people lined up outside the Showbox SODO for a metal show, their scowls softened.

“Bill Nye the Science Guy! I watched you all the time, man!”

Two young women walked right past Nye along First Avenue before one stopped in her tracks and turned back to look at Nye.

“Holy shit!”

Nice as such adoration may be, this wasn’t really Nye’s plan.

He graduated from Cornell, was a Boeing engineer and was working at Sunstrand Data Control (now Honeywell) when his desire to write and perform comedy got the better of him. He quit his job in 1986 and went for it.

His stand-up was “mediocre,” he said, “one hilarious engineering joke after another.” People recognize engineers at parties because their pants don’t reach the floor. That sort of thing.

He started writing for the Seattle-based sketch show, “Almost Live.” That led to “Bill Nye the Science Guy,” which led to national television work, which led to 20 years later and the first pitch at Safeco.

The question is whether Nye can remain the subject of such affection as he evolves from a childhood icon to a sober, scientific voice in the political debate over subjects like climate change and creationism.

It’s almost as if Mister Rogers had begun speaking out on birth control. We would definitely not be in the neighborhood anymore. And with Nye, we’re no longer in the lab. He’s gone from blowing things up to shooting theories down, all in the name of our very future.

“We’re vertently evolving, not inadvertently,” Nye said of his new role. “We did a kid’s show and made a statement. Now we’re off doing something else.

“I have no trouble taking these political stances, because I think the evidence is overwhelming,” he said. “I can demonstrate that the earth is not flat and in the same way, with enough diligence, I can demonstrate that the Earth is not 10,000 years old. So, to use tax dollars to teach that as an alternative to scientific facts is inappropriate.

“Denying science is in nobody’s interest.”

Empirical evidence is one thing, but lately Nye has become more forthright about the ideological battles surrounding science.

“Conservatives are so far to one side that things are a little out of balance,” he insisted. “To run around in these certain congressional districts trying to change science education to fit this wrong idea is inappropriate … We are all hopeful in the scientific community that change will happen sooner rather than later. ”

Sentiments that may be alienating to some of his fans, but ones he is showing no signs of tempering. On our outing, Nye was being trailed by two documentarians working on a film about Nye called “Objective: Change the World” that they plan to shop to Showtime.

He’s also writing an adult book about energy.

“We could save one-third of the energy we produce in very easy ways,” he said. “It’s low-hanging fruit like insulating windows.”

For a guy advocating for window insulation, Nye sure is popular.

Even on the field, when the Marines spilled into the dugout before the game, each one looked up and said Nye’s name out loud. Mariners GM Chuck Armstrong threw his arm around him.

Mariners ball boy John Feltner, 26, is actually a microbiologist — an accomplishment inspired by Nye.

“He’s one of the reasons I got into my profession,” Feltner said. “He and ‘The Magic School Bus.’ I just really liked the show. Cool science. You could have fun doing it.”

But this evening, it’s Nye who is having fun. He asked for seats in the 300 section behind home plate — the best view of the pitches, the batters, the field.

“Wow, that’s a strike?” Nye muttered to the distant ump. “You are blind, you are, totally blind. I can see it perfectly from here.”

Of his own field, Nye said, “I didn’t feel I was in the position to become a captain of industry … I love the scientific method. I love the discoveries that humans have made. So whenever I am given a chance to discuss that, bring it on.”

So, that’s his pitch. And we’ll see how it goes as he ventures deeper into the fraught political debates around many scientific issues.

And his actual pitch? It was, if you must know, a little to the right, and a little short — a quick bounce at the plate.